1. Field of the Invention
The present invention relates to a breather system for a transmission in which a plurality of gear shift stages are selectively established by moving shift forks by means of a shift select shaft, moving in an axial direction according to a select operation of a shift lever and moving in a circular manner according to the shift operation thereof.
2. Description of the Prior Art
A transmission containing a breather chamber is known in U.S. Pat. No. 4,446,755. This breather chamber is formed from a rib which is connected to the inner wall surface of a transmission case and a rib which is connected to the inner wall surface of a clutch case, to bridge the connecting surface between the two cases, and the breather chamber is connected through to the internal space of the transmission case via a notch formed in the rib.
However, since a special breather chamber is formed on the connecting surface between the transmission case and the clutch case in the prior art, not only does the overall size of the transmission increase due to the volume of the breather chamber, but also maintenance of the breather chamber cannot be carried out without separating the transmission case from the clutch case, which is an extremely troublesome operation.
The present invention has been carried out in view of the above-mentioned circumstances, and it is an objective of the present invention to form a breather chamber whose maintenance is easy while avoiding an increase in the size of the transmission case.
In order to achieve the above-mentioned objective, in accordance with the present invention a transmission breather system is provided which is a breather system for a transmission in which a plurality of gear shift stages are selectively established by moving shift forks by means of a shift select shaft, moving in the axial direction according to a select operation of a shift lever and moving in a circular manner according to a shift operation thereof. A subassembly is formed by supporting the shift select shaft and a select spring, which maintains the shift select shaft in a neutral position, on a cover member. A breather chamber is formed between the cover member and an indentation formed in a transmission case by inserting the shift select shaft into an opening formed on the bottom wall of the indentation of the transmission case so as to connect the cover member to the transmission case, and the select spring is housed in the breather chamber.
In accordance with the above-mentioned arrangement, since the subassembly is made by supporting the shift select shaft and the select spring on the cover member and the shift select shaft of the subassembly is inserted into the opening formed on the bottom wall of the indentation of the transmission case to connect the cover member to the transmission case, not only does the operation of assembling the shift select shaft and the select spring become easy, but also the space required for housing the select spring can be used as the breather chamber, contributing to a reduction in the size of the transmission case. Moreover, maintenance can be carried out by simply removing the subassembly from the transmission case to expose the internal space of the breather chamber.
Furthermore, in accordance with the:present invention, a breather system for a transmission is proposed wherein a spring seat for supporting one end of the select spring is supported on the bottom wall of the indentation, and the breather chamber is connected through to the internal space of the transmission case via a through hole which is formed between the outer circumference of the spring seat and the inner circumference of the opening.
In accordance with the above-mentioned arrangement, since the breather chamber is connected through to the internal space of the transmission case via the through hole between the outer circumference of the spring seat for supporting one end of the select spring and the inner circumference of the opening of the transmission case, it is possible to prevent oil inside the transmission case from entering the breather chamber.